The invention is related to an electric switch unit for automotive vehicles in which a cable, particularly a flat cable, leaves the housing. More particularly, the invention relates to an electric switch unit in which the housing is provided with a strain relieving means such that the exit of the cable from the housing is realized at a preset exit angle.
Electric units, also switch units, are known in which it is of special importance that the cable leaving the housing be strain-relieved within the housing in such a way that the functioning of the unit is not impaired or even interrupted by the strains acting on the cable from the outside. Strain-relieving means are known which are self-contained components in electric units such as miniature motors, electric switches and other similar devices. It is a disadvantage of these solutions that the strain-relieving means are incorporated as a self-contained component part into another component part, thereby increasing cost and assembly efforts.
From the German patent application No. G 87 01 965.5 a strain relieving means is known which is composed of two parts fitting into each other leaving a free space between them for the insertion of a cable. Beyond the disadvantage of the separate component, this solution presents a relatively sophisticated shape. Moreover, the cable needs to be pressed into the free space between the two parts, such that tight cable routing must be observed in this context.
A further strain-relieving means is known from the German patent application No. 2,607,702 in which a cable is turned around a separate element several times. Although this strain-relieving unit works very reliably, a great deal of space is occupied by the assembly.
In German patent application No. G 85 23 264.5, a lamp holder with a strain-relieving component molded to the lamp holder is described. The mode of operation of this strain-relieving device mainly consists of the cable being turned around the strain-relieving device.
In addition, a plug-in connection with a strain-relieving means is known from German patent No. 3,041,938 C2 in which, similar to the other strain relieving means, the cable is turned around the strain-relieving means several times. As a result, tractive forces which may occur are transformed into frictional forces at the deviating points with the consequence that no remarkable tractive forces come to act on the cable. In the patent specification, various cable exit angles from the housing are disclosed but a limitation is chosen in favour of two possibilities of cable exit, longitudinally and vertically to the housing of the electrical assembly. In the case of unsheathed cables, the exit of the cable at a determined angle can be reliably realized when the free end of the cable is subjected to a tractive force. Only then will the cable adhere to the edge of the housing exit such that the exit angle can be determined.
Without the free end of the cable undergoing the tractive force, the angle of exit of the cable from the housing cannot be stably adjusted. Sheathed cables can be fixed within the housing at their sheathing. As a result, two exit angles, disposed vertically with respect to each other, can be realized.
It is a common characteristic of all strain-relieving means that they fail to provide a reliable way to realize a cable exit at any optional and preset angle. Consequently, the cable must be deviated into the desired direction upon its exit from the housing, which in the case of delicate electronic elements, may even lead to their destruction. Disadvantageously, the cable leaving the housing must be subjected to a tractive strain to be bent into a desired direction, so as to be assembled at a preset angle.